How to grow tomatoes

Some 8,000 varieties of Solanum lycopersicum are grown worldwide, yielding a crop of about 130 million tons of tomatoes per annum. It is an astonishing success story for a plant that first penetrated human consciousness as a toxic herb in one of the remotest places on the planet.

Tomatoes trace their roots to the Peruvian Andes and wild species that nobody in their right mind considered edible. These were used not for their fruit, but for their foliage, which contained psychoactive chemicals. Sometime in the first millennium BC, they were carried north to Mexico.

There, they prospered, becoming a weed of fields and gardens, and it was there that somebody took the brave step of tasting their fruit and pronouncing it edible. Direct descendants of these plants can still be found in parts of Mexico, grown and eaten as they were in pre-Columbian times. Around the town of Zinacantán in the far south-west, an ancient variety uncannily like the modern cherry tomato forms the basis of a hearty stew. I won’t trouble you with the recipe, except to say that it includes jerked meat, snails and iguana.

It was further north, among the Aztecs and between the 14th and 16th centuries, that these plants acquired the name by which the world would come to know them -tomatl or tomato. For such a global brand, it took an age to become established. When Spanish conquistadors returned with this novel crop, Europeans seemed to want to call it anything but tomato. Describing this newcomer in 1544, the Italian botanist Pierandrea Mattioli named it pomum aureum or pomi d’oro-‘golden apples’-so evoking the mythical fruit that grew in the garden of the Hesperides, and suggesting that his specimens were yellow-skinned rather than red. Even in the Mediterranean countries that would become tomato cultures, these fruits were at first considered foreign muck.

In the collective imagination, they became associated with people who were, likewise, deemed undesirable aliens. This prejudice produced the names by which tomatoes would be known in Europe until the end of the 18th century: poma amoris, pomme d’amour, Liebesapfel, and love apples. These, alas, do not hint at miraculous aphrodisiac powers; they all derive from pome dei Moro, ‘Moor’s apple’.

In England, love apples were slow to win hearts. Their unpopularity is often attributed to the herbalist John Gerard, who is said to have declared them poisonous. In fact, he did nothing of the kind. In his Herbal of 1597, he talked about the apples of love that grew rampantly in his Holborn garden. He also noted that our Continental cousins had overcome their initial misgivings, eating tomatoes either fresh with pepper, salt and oil, or as ‘sauce to their meate, even as we in these cold countries do mustarde’.

The problem, said Gerard, was not toxicity, but the fact that tomatoes were ‘cold’ fruit, with little nutritional value. The idea that people in cold countries needed hot and heavy food was accepted medical opinion in Gerard’s day. There was no Elizabethan Elizabeth David. Anglo-Saxon suspicions persisted for at least 200 years. In 1753, Chambers Cyclo-paedia at last recorded the name ‘tomato’ as standard, but declared disdainfully that its fruit was not eaten by Englishmen.

A century later, the American philosopher Ralph Waldo Emerson wrote that tomatoes, like olives, were an acquired taste, and a taste no gentleman would acquire. Only interaction with foreigners would finally win us over to this foreign fruit. In our case, this meant empire in 1845 and 1855, for example, the cookery writer Eliza Acton launched two momentous phrases on the unsuspecting English, tomato ketchup (from Cantonese, k’e chap), and tomato chutney (from Hindi, catni).

For Emerson and other WASPs, it was the southern European immigrants who were landing on US docks. By the 1920s, the tomato was such a beloved staple of American life that the word became slang for the kind of girl who might be the apple of one’s eye: pomme d’amour had found its mark.

There were still controversies to come. In 1937, Fred and Ginger famously disagreed on the pronunciation of tomatoes. As nomenclatural rows go, however, Let’s Call the Whole Thing Off was nothing compared to the scandal that was Ketchupgate. In 1981, the Reagan administration attempted to have ketchup designated as a vegetable for the purposes of state-funded school lunches.

The idea was to save money wasted on giving children greens that they showed little inclination to eat anyway. But the president may not have been such a spinach-snatcher after all. According to recent medical studies, large quantities of lycopene, the pigment that makes tomatoes red, may reduce the risks of cancer and cardio-vascular disease. What’s more, lycopene becomes more useful in tomatoes that have been cooked and reduced, puréed, or turned into the dreaded ketchup. More anecdotally, tomatoes are hailed as happy food, alleviating depression; could its effect be due, however, to the occupational therapy of making bolognese, or the possibility that a stiff-enough Bloody Mary will cure anything?

There is also a widespread belief that tomato-guzzling cultures are happier and healthier. Only this could explain the unstoppable spread of that offence against good English, the ‘sun-dried’ tomato-Mediterranean hankerings in mummified form. But, for my money, few things are more restorative than entering a glasshouse full of tomatoes and inhaling deeply. Perhaps those Peruvians were right in the first place?

What to grow, where

Tomatoes’ diversity is immense, and eating one freshly picked and still warm from the summer sun is a heavenly experience everyone should sample. They can be found in numerous shapes and sizes: classic, beefsteak, plum, cherry, cherry plum and currant. Apart from the familiar reds, orange and yellows, their colour range includes rose-reds, creams and greens.

Modern varieties tend to boast disease resistance and crop reliably, but ‘heritage’ or ‘heirloom’ varieties often have intriguing histories, although they can be indifferent crop producers. However, the latter are often open-pollinated, which means their seeds can be saved from year to year-a big advantage to some people.

Different habits of growth are also defining features: cordon or indeterminate tomatoes that keep on growing throughout the season, bush or determinate types that don’t, and dwarf size tomatoes.

Flavour depends on many factors: the quantity and quality of sunshine, prevailing temperature, the quantity of water uptake, the amount and type of feeding they have received, the type of compost, the position of the plant indoors or outside. Also, of course, the variety itself: some are definitely sweet, but others have a more savoury finish (although we can all disagree on which tomato has the best flavour).

In my experience, glasshouse-raised cherry varieties grown as cordons give the most consistent results, and our recent favourites include Rosada F1, Cherrola F1, Chocolate Cherry, Piccolo F1 and Nectar F1. Sungold is always a good bet, too. The huge trusses produced by all of the above and their consequent productivity are a boon, so they are my first choice.

However, a close second are the exotically named heritage beefsteak varieties with appellations such as Aunt Ruby’s German Green, Hillbilly Potato Leaf, Black from Tula, Brandywine, Marizol Gold and Rose de Berne, all of which are good to grow.

Sowing time for tomatoes varies depending on your location in the country and on the final destination of the plant-either outdoors or under glass. Indoor varieties can be sown earlier than those destined for outdoors, and, with these, we aim to plant them out in late May or early June after frosts so their sowing time is early April.

The sowing date of those planted indoors depends on whether the glass is heated or not. For heated glass, an early March sowing is sufficiently early for most people, and for unheated glass, late March will do.

Tomato seed germinates readily in a propagator set at about 15˚C. Use clean, disinfected module trays or individual pots if you’re recycling and a good seed-raising compost of your choice. Bright light is essential for a sturdy growth, which can be supported with a split green cane at the very first sign of stem flop.

For all tomatoes, we sow individually into 3in-diameter plastic pots, and pot up when the plant is big enough into a half loam base, half all-purpose mix, first into a 6in pot, and then for indoor varieties into a range of terracotta pots in different sizes depending on their ultimate size and location.

These can range from 6in diameter for a variety called Micro Tom (a curiosity) up to 16in diameter pots for vigorous cordon varieties such as Ildi, which we tie up to the glasshouse rafters and allow to develop seven or eight trusses or more. Some crops are planted into glasshouse borders to grow up against a back wall or as double cordons in a shallow trench in another glasshouse.

Once established, indoor tomatoes benefit from an early morning watering when there’s a surge in growth and another, ideally mid afternoon, if required; try and avoid late-evening watering if the plants are grown under glass because of potential fungal problems with the associated high humidity from watering. If grown outside, choose a sunny, sheltered position preferably against a wall for additional warmth and to help keep the foliage dry, which assists in the battle against blight-a fungal disease that’s the scourge of tomatoes grown outdoors.

Nearly all tomato varieties benefit from staking, with three-ply twine and split green canes for the smaller determinate varieties or a bamboo cane up held against a wall or five-ply strung up from the base of the plant to a glasshouse rafter for the bigger types.

For indoor cultivation, start by feeding young plants with a weak seaweed extract solution, follow up with a balanced fertiliser until a couple of trusses of flowers appear, then change to a tomato feed that’s higher in potash and helps to promote further flowers and fruit. Dilute a weekly fertiliser recommendation by seven and apply the smaller amount daily with the first watering.

Remove the side shoots-that is, those that appear between the main stem and a leaf of indeterminate (cordon) varieties on a regular basis to control the growth of the tomato, which will take over if left unattended. For determinate (bush) varieties, this isn’t required, although judicious removal of some leaves (not side shoots) on hanging basket types (for example, a variety called Hundred and Thousands) will help maintain air flow and reduce localised humidity.

Once the indeterminate plant has produced about 4-6 trusses (fewer on outdoors crops and more indoors), take out the growing tip so that energy returns back down the plant to help ripen remaining fruit.

The number of trusses you allow to develop depends on the quality of your plant, the time left in the season for the tomato to ripen and the room you have to grow it in. Bush or determinate varieties branch and stop naturally, so there’s no need to pinch out the growing tip.

Once they’re harvested, remember to store tomatoes at room temperature and not in the fridge, as that’s the fastest way to kill the flavour.

And finally, to find out much more about tomatoes, come along to the Totally Tomato Show at West Dean Gardens on September 4-5. For further details, telephone 01243 811301 or visit www.westdean.org.uk

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